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प्रश्न
Explain the following reaction with a suitable example.
Hofmann elimination reaction
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उत्तर
- When tetraalkylammonium halide is heated with moist silver oxide, it gives quaternary ammonium hydroxide.
- Quaternary ammonium hydroxides on strong heating undergo β-elimination to give an alkene. This reaction is called Hofmann elimination.
- The least substituted alkene is obtained as a major product (in contrast to Saytzeff elimination).
e.g. Hofmann elimination reaction of N, N, N-Triethylpropylammonium iodide
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संबंधित प्रश्न
How is ethyl amine prepared from methyl iodide?
How are propan-1-amine and propan-2-amine prepared from oxime?
Illustrate the following reaction giving suitable example in each case:Gabriel phthalimide synthesis
How do you convert the following: Ethanenitrile to ethanamine
Write a short note on the following:
Hoffmann’s bromamide reaction
Give the structure of A, B and C in the following reaction:
\[\ce{C6H5N2Cl ->[CuCN] A ->[H2O/H+] B ->[NH3][\Delta] C}\]
Give the structure of A, B and C in the following reaction:
\[\ce{C6H5NO2 ->[Fe/HCl] A ->[NaNO2 + HCl][273 K] B ->[H2O/H+][\Delta] C}\]
Why cannot aromatic primary amines be prepared by Gabriel phthalimide synthesis?
Write the reaction of aliphatic primary amine with nitrous acid.
Explain the mechanism of action of hydroiodic acid on 3-methylbutan-2-ol.
Mention 'two' uses of propan-2-one.
Give the structures of A, B and C in the following reactions :
Give the structures of A, B and C in the following reactions :
Give the structures of A, B and C in the following reactions :
Account for the following:
Gabriel phthalimide synthesis is not preferred for preparing aromatic primary amines.
The following amines is the product of Gabriel phthalimide synthesis.
Name the process of breaking C-X bond by ammonia in preparation of amines.
Write the order of reactivity of alkyl halides with ammonia.
Explain Hoffmann’s exhaustive alkylation with suitable reactions.
Why cannot aniline be prepared by Gabriel phthalimide synthesis?
Acetamide on reduction using Na/C2H5OH gives ____________.
Identify the product 'A' in the following reaction.
\[\ce{Aniline ->[(CH3CO)2O][Pyridine] A}\]
The end product C of the following reaction is
\[\ce{C2H5NH2 ->[HNO2] A ->[PCl5] B ->[NH3][Alcohol] C}\]
Identify the product obtained, when benzamide is treated with bromine and aqueous sodium hydroxide.
What is the molar mass of the amine formed when acetamide undergoes Hofmann bromamide degradation?
Identify the product obtained when benzamide is treated with bromine and aqueous sodium hydroxide?
In aqueous phase the order of basic strength of alkylamine is ______.
Which of the following reagents is used in Mendius reduction reaction of alkyl cyanide?
Identify product B in the following reaction.
\[\ce{Aniline ->[NaNO2][HCl] A ->[KI] B}\]
Which of the following reagents is used in Hofmann's elimination reaction of amines?
Which of the following compounds is obtained when quaternary ammonium hydroxide is strongly heated?
Which of the following reactions does NOT yield an amine?
Nitro compounds are reduced by iron scrap and hydrochloric acid to yield one of the following compounds:
Quaternary ammonium salt is formed:
Benzylamine may be alkylated as shown in the following equation:
\[\ce{C6H5CH2NH2 + R - X -> C6H5CH2NHR}\]
Which of the following alkylhalides is best suited for this reaction through SN1 mechanism?
The source of nitrogen in Gabriel synthesis of amines is ______.
Best method for preparing primary amines from alkyl halides without changing the number of carbon atoms in the chain is ______.
Which of the following methods of preparation of amines will give same number of carbon atoms in the chain of amines as in the reactant?
Reduction of nitrobenzene by which of the following reagent gives aniline?
(i) \[\ce{Sn/HCl}\]
(ii) \[\ce{Fe/HCl}\]
(iii) \[\ce{H2 - Pd}\]
(iv) \[\ce{Sn/NH4OH}\]
Which of the following reactions are correct?
(i)
(ii)
(iii)
(iv)
Under which of the following reaction conditions, aniline gives p-nitro derivative as the major product?
(i) Acetyl chloride/pyridine followed by reaction with conc.\[\ce{H2SO4 }\] + conc. \[\ce{HNO3}\].
(ii) Acetic anyhdride/pyridine followed by conc.\[\ce{H2SO4}\] + conc.\[\ce{HNO3}\].
(iii) Dil. HCl followed by reaction with conc.\[\ce{H2SO4}\] + conc.\[\ce{HNO3}\].
(iv) Reaction with conc.\[\ce{HNO3}\] + conc.\[\ce{H2 SO4}\].
Identify A and B in the following reaction.
How will you bring out the following conversion?
Assertion: Aromatic 1° amines can be prepared by Gabriel Phthalimide Synthesis.
Reason: Aryl halides undergo nucleophilic substitution with anion formed by phthalimide.
The Gabriels' phthalimide synthesis is used in the synthesis of
The compound X is which of the following?
\[\ce{CH3CN ->[Na + C2H5OH] x}\]
Ethylamine can be prepared by the action of bromine and caustic potash on which compound?
When primary amines are treated with HCl, the product obtained is which of the following?
Which of the following CANNOT be prepared by ammonolysis of alkyl halide?
What is the IUPAC name of \[\ce{(CH3)2 - N - CH3}\]?
Identify the product ‘C’ in the following reaction.
\[\ce{Aniline ->[(CH3CH)2O][Pyridine] A ->[Br2][CH3COOH] B ->[H^+ or OH^-] C}\]
Write the name of the product formed by the action of LiAlH4/ether on acetamide.
Identify A and B in the following reaction.
\[\ce{C6H5CH2Br ->[Alco.][KCN] A ->[Na/Ethanol][reduction] B}\]
Write short note on the following.
Ammonolysis.
